1-cyclohexyl-3, 3-dialkylureas and their use as herbicides



Patented Dec. 1, 1953 UNITED STATES PATENT OFFHIE 1-CYCLOHEXYL-33-DIALKYLUREAS AND THEIR. USE AS HERBICIDES Norman E. Searle, Wilmington, Del., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware N Drawing. Application September 21, 1950, Serial No. 186,116

Claims.

containing N-cycloaliphatic urea compounds.

The enormous economic losses caused by weeds have, to some extent, been relieved in recent years with the advent of 2,4-dichlorophenoxyacetic acid (2,443), trichloroacetic acid and related synthetic chemicals. These products, however, have not been particularly successful in the control of certain weeds such as Johnson grass, Bermuda grass, nut grass, quack grass and the like. Effective herbicidal materials for the control of these and other plants resistant to the presently available products are much needed.

It is an object of this invention to provide a new class of N-cyclohexyl ureas and methods for their preparation. A further object is to provide herbicidal compositions containing N-cycloaliphatic urea compounds as an essential active ingredient. Other objects will appear hereinafter.

The objects of this invention are accomplished by providing new i-cyclohexyl-3,3-dialkyl ureas .and novel herbicidal compositions containing as and grass weeds can be successfully controlled by the new herbicidal compositions of this invention containing as essential active ingredients N-cycloaliphatic urea compounds in which the '2-carbon atom of the urea linkage,

I it I is doubly bonded to a chalcogen, X, of atomic number less than 17, i. e., oxygen and sulfur, and

having directly attached to the urea nitrogen atoms one monovalent cycloaliphatic, preferably saturated, hydrocarbon radical, and, through saturated carbon, (n-l) aliphatic acyclic mono- 2 valent hydrocarbon, i. e., alkyl and alkenyl, radicals, n being an integer less than 5. These urea compounds are of the formula wherein A is the cycloaliphatic hydrocarbon group, X is the definedchalcogen, and the. R groups are hydrogen, alkyl and alkenyl.

Of this group a new class of oxygen ureas, i. e., the chalcogen, X, is oxygen only, having hydrogen on the urea nitrogen which is nuclearly bonded to a cyclohexyl radical and two alkyl radicals of up to eight carbon atoms on the other urea nitrogen atom is provided by this invention. This new class can be represented by the general formula,

wherein R and R are alkyl radicals, preferably of from 1 to 8 carbon atoms.

The ureas of this invention can be prepared by conventional methods, for example, by reaction of aliphatic primary and secondary amines and in certain cases their salts, e. g., mineral acid salts, with an isocyanate isothiocyanate, carbamyl chloride or thiocarbamyl chloride. The following equations illustrate more specifically these various methods which can be suitablyemployed for'the preparation of representative ureas embraced in this invention:

The above reactions are accomplished by OHPC 1 bringing the amine or, in cases indicated, their CHz-CH: S

| salts in contact with one of the reactants speci- /CH IITJJ NHCHT'CH=CH' fied, usually in chemically equivalent amounts,

CH3'CH2 H 55 and, if necessary, heating to reaction tempera- 1-cyclohexyl-Z-thio-S-ailylurea ture. A suitable procedure consists in slowly adding at a temperature of 0 to 100 0., preferably (4) CHFOH, 15-75 C., the organic isocyanate, isothiocyanate, NGS carbamyl chloride, or thiocarbamyl chloride to C CHNHCH"+ 7 the selected amine, preferably employed in molar 0117-0 1 excess, e. g., 10-20%, dissolved or suspended in an CHFCH i inert liquid medium such as dry dioxane, dry 0 N NHCHTCH=CH1 benzene, dry dibutyl ether, dry toluene and the CHFC like, and. continuing the reaction until com- Mw]obm,H methy1 2 tm 3 auy1urea 75 pleted. Ordinarily this does not require more than two to three hours after the reactants have been thoroughly mixed, e. g., by stirring, at the specified temperature. I

The isocyanate, carbamyl chloride, or thiocarbamyl chloride can also be dissolved or suspended in inert liquid media similar to those employed with the amine. Two to twenty parts of inert liquid reaction medium, i. e., diluent, to each part of amine or other specified reactant will ordinarily be satisfactory.

When employing an inorganic isocyanate or thiocyanate with an amine salt in accordance with Methods A (1,2) and B (1,2), water is a most suitable liquid reaction medium. It is of advantage when carrying out reaction with the carbamyl or thiocarbamyl chlorides (Methods 0 and D) to use an acid acceptor, e. g., a tertiary amine such as triethylamine, dimethylaniline, pyridine, etc., ordinarily dissolved or suspended in inert diluent with the amine. Generally, it is desirable to carry out the first part of the reaction at moderate temperature, e. g., Iii-35 C., and then slowly increase the temperature, if necessary, to complete the reaction.

The new 1-cyclohexyl-3,3-dialkylureas are, for the most part, solids and can be isolated by crystallization, extraction or other suitable means. For example, when dioxane or other inert water-miscible reaction medium is employed, the new solid 1-cyclohexy13,3-dialkylureas of a satisfactory degree of purity can usually be isolated by cooling or diluting the reaction mixture with water and removing the precipitated urea by filtration. If desired further purification can be achieved through crystallization, in most instances from dioxane or benzene, or a mixture of these solvents.

The ureas defined herein can be incorporated with various materials to prepare the new herbicidal compositions of the invention either in liquid or solid form. For example, solutions of the ureas in organic solvents such as cyclohexanol, furfural, isobutanol, isopropyl acetate and the like, can be applied directly as herbicides. This method of application, however, is uneconomical and generally impractical. Suitable compositions are prepared by admixing or dispensing the ureas with a non-solvent carrier which may be either solid or liquid. Thus herbicidal dust compositions are compounded to give homogeneous free-flowing dusts by admixing the ureas with finely divided solids, preferably talcs, natural clays, prophyllite, diatomaceous earth, and flours such as walnut shell, wheat, redwood, soya bean and cottonseed flours. Other inert solid carriers which can be used to prepare the herbicidal compositions include magnesium and calcium carbonates, calcium phosphate, sulfur, lime, etc. either in powder or granular form. The percentage by weight of the essential active ingredient will vary according to the manner in which the composition is to be applied to the plants, but in general will be 0.5 to 95% by weight of the herbicidal composition.

Liquid herbicidal compositions consist for example of the ureas homogeneously dispersed in water or other non-solvent carrier. To secure such homogeneous dispersions a surface-active agent is used. In fact, the preferred herbicidal compositions of this invention, whether in liquid or in solid form contain the ureas homogeneously admixed with a surface-active agent, sometimes referred to in the art as wetting, dispersing, or penetrating agents. These agents cause the compositions to be easily dispersed. in water to give 6 aqueous sprays which, for the most part, can stitute a most desirable method of application.

The surface-active agents employed can be of the anionic, cationic or nonionic type and include, for example, sodium and potassium oleates, the amine salts of oleic acid such as morpholine and dimethylamine oleates, the sulfonated animal and vegetable oils such as sulfonated fish and castor oils, sulfonated petroleum oils, sulfonated acyclic hydrocarbons, sodium salts of lignin sulfonic acid (goulac), alkylnaphthalene sodium sulfonate, sodium salts of sulfonated condensation products of naphthalene and formaldehyde, sodium lauryl sulfate, disodium monolauryl phosphates, sorbitol laurate, pentaerythritol monostearate, glycerol monostearate, diglycol oleate, polyethylene oxides, ethylene oxide condensation products with stearyl alcohol and octylphenol, polyvinyl alcohols, salts, such as the acetate, of polyamines from reductive amination of ethylene/carbon monoxide polymers, laurylamine hydrochloride, laurylpyridinium bromide, stearyltrimethylammonium bromide, cetyldimethylbenzylammonium chloride, lauryldimethylamine oxide, and the like. erally, the surface-active agent will not comprise more than about 5 to 15% by weight of the composition, and in certain compositions the percentage will be 1% or less. Usually the minimum lower concentration will be 0.1%.

The herbicidal compositions of the invention can also have incorporated therein oils, fats or similar vehicles such as, cottonseed oil, olive oil, lard, paraffin oil, hydrogenated vegetable oils, etc. Adhesives such as gelatin, blood albumin, resins, for example, rosin, alkyd resins and the like, can also be used in certain compositions to increase retention or tenacity of deposits following application.

Concentrated water-dispersible liquid compositions can be prepared by incorporating with the ureas and surface-active agents various organic liquids such as furfural, methanol, isopropanol, isobutanol, xylol, cyclohexanol, cresol, cyclohexanone, acetone, methyl ethyl ketone, kerosene, trichloroethylene, dimethylformamide, dimethylacetamide, alkylated naphthalenes, and the like. Such compositions are readily dispersible in water and provide excellent aqueous herbicidal sprays for field application. The proportion of surfaceactive agent to urea can be 0.1 to 100% by weight in these water-dispersible herbicidal compositions.

In another method of application for weed control, the ureas of this invention are incorporated with fertilizers to form either powdery or granular herbicidal compositions that can be used in the cultivation of agricultural crops. 7

A more detailed practice of the invention is illustrated by the following typical examples, in which parts, unless otherwise specified, are by weight:

Example I Dry hydrogen chloride was introduced into a solution of 99.2 parts of cyclohexylamine in 1000 parts of dry dioxane until the gas was no longer absorbed. A suspension of the cyclohexylamine hydrochloride had formed. Phosgene was then passed into the stirred suspension of amine salt while heating at -90 C. and until a clear solution resulted. Excess phosgene and hydrogen chloride were removed by distilling 450 parts of the dioxane with the pot temperature at 104 C.

Into one-half of this solution of cyclohexyl iso-.

cyan te w s passed d me y ene wh lemainta ne ing the reactiontemperature at, about 45 C. by ex ernal coolin After abs rn i no he d me ylamine wascompleted. the r a on. was heated allam? C- o m ute and then o ed t 25 C. The. 1-.cyclohexyl -.3., 3dimethylurea was then: prec pi ated fromthe reaction. m x ur wi h water and. filt washed w th. c d wa e and dried. in a vacuum es ccator ov r ph pho ous nentoxideh r in snow-white n lesv o .-cy,cloh xyl.-.3.3- dimethyl rea amount d to 47 parts. and me1ted.a.t15.7.2 .1 58 C sso ub ein hot water a d ky at d ap ha ene e1 ico1 AB-501 solvent to the extent of ut five.- pen cent.

Analicaicfi. for CsHreNzQ: N, 16.4.5%; Found: N. 16.58%-

Other dialkyl amines. whi h can e conv rted. to. the rr spond n +cy l hexyl-3fi d a ylu: reas y substitutin e mo r roporti ns pecified 01: e. dimet ylaminein the above ex: ample nclude. the d ethyl. d D TODYL, dibut amyl. di xyl. dihep y di ctyl, methyl-is uty methy ethyL. et yl. s pr nyl. amines an t e like.

Thuaior example, L-cyclohexyl-S,Bediethylurea; L

1-cyclohexyle3,3adihutylurea; l-cyclohexyl 3,3- di c ylur a; and. e y ohexyw e y -a ethylurea can be.- obtained y p per ho e fr m th foregoing dialkylamines named.

Example II A one pe cent. acet ne so u on o l-Wclohex r3d-dimethylureaspray on Johnson rass seedlings resul d. in. subs a tia y comple hil of his esis ant. plan Exam le I A liquid composition was prepared by thoroughly admixing 0.2 partof l-cyclohex-yl-ISS-dimethylurea, 0.8 part of morpholine oleate, and 2 parts of a 50:50 mixture of'isopropanol and alkylated naphthalene (Velsicol AR-SQ). This composition is readily dispersible in water and provides an aqueous spray composition suitable for herbicidal application.

Example. 1V

Twenty (20) parts of 1-cyclohexyl-33-dimethylurea is homogeneously blended with 80 par-ts of talc byplacing in a micropulverizer' mill and pulverizing the mixture until a particle size of about 50 microns is attained. This product provides a homogeneous free-flowing powder suitable for application as a herbicide.

Additional ureas which can be employed in the herbicidal compositions of this invention include 1- (l-menthyl) -3-allylurea, 1- (l-menthyl) -3butylurea, 1- ('-1-menthyl) 3,3diethy-lurea, 1- (menmethylurea, 1-cyclohexyl-2-thio-3,3-diethylurea, 1-cyclohexyl-2-thio-3-isopropylurea,1 -cyclohex ylurea, l-cyclohexyl-hmethylurea, l-cyclohexyl- S-methylurea, 1-cyclohexyl-2-thio-3-allylurea, 1- eyolohexyleLthio-fi-butylurea, lecyclohexyl. 2- thio-3.-.ethylurea, and the like.

Although. this. invention embraces, broadly ureas and thioureas having as. substituents on the. urea. nitrogen atoms but onemonovalent cycloaliphatic hydrocarbon radical and up to three aliphatic acyclic hydrocarbon, i. alkenyl. radicals, the ureas wherein the chalcogen, in the previously described formula. is oxygen are preferred over the corresponding sulfur analogs in view of somewhat higher herbicidal activity. Because of availability of prepare alkyl and ative raw. materials, the cycloaliphatic hydrocarbon group is preferably a saturatedmononuclear cycloaliphatic group of six annular carbons. In preparing theherbicidal compositions of the invention the more desirableureasare those hav ing a hydrogen atom attached to the urea nitrogenv bearing the nuclearly bonded cycloaliphatic hydrocarbon group and from one to two aliphatic acyclic hydrocarbon radicals on the other urea nitrogen atom, particularly alkylradicals of up: to two carbon atoms. For certain other uses, as,;in plasticizers. and the like, the higher alkyl groups of up. toeight. carbonatoms in the new lwcyclohexyl-3,3-dialkylureas are usually advantageous.

The solid and liquid compositions described and employed. herein for application of the essential active herbicidal ingredient all have the common property of permitting application of the herbi cidal compositions through suitable jets, nozzles, or Spreaders adapted to the. handling of: granular materials onto the plants beingtreated andwill', for convenience, be. designated as fluent. oarriers. The fluent carriers with which. this in,- vention is primarily concerned are non-solvent fluent carriers,

The new 1-cyclohexyl3,3-dialkylureas of; this invention, in addition to their, utility in herbicidal compositions, are also useful as conditioning agents for waxes, as modifiers for resins,- and plastics, and as chemical intermediatesior the manu-- facture of pharmaceuticals.

As many apparently widely different embfldiw ments of this invention may be madewithout departing from the spirit and scope thereof; it is to be understood that this. invention, is. not limited to the specific embodiments thereof; except as defined in the appended claims.

1 c aim;-

1.A herbicidal c mpos ti n omprising: as: an s nt l. a tive ingredient, homogeneously is.- pe sed ima no -solven t. carrier, a com.- p und. havin t tormula n-ar-oqe-n, i t l wherein A is. cyclohexyl. and. R. and, Rf are; alkyl radicals.

2. A herbicidal. composition. comprising; a. surface-active; agent, and as an. essential active. in radient n. dmixture. the with. a comp und ha i g the ormula.

AwNrCe-NwRQ g; t.

h r in A, cyclohex l and. Ha dle! are alky adicals.

3 A1. herb c dalmp sition. compri g as an essential" active ingredient homogeneously dis.- p rs i n anon-solvent. fluent carrier. with asunf c ract y agent. a. compound h v ng them.- mula.

AFNTC' N R{ a Q i wherein A is cyclohexyl and R and R are alkyl radicals.

4 A. herbicidal composition comprising as. an essential active ingredient: homogeneously dis- Persed in. a. non-solventc fluent carrier; B-cyclohexyl-3',3:-.dimethylurea-.

5; A herbicidal oomposition comprising a surface-active agent and as anessential active ingredient in admixture therewith; L-cyclohexyl- 333-.dimethylurea.

6: A: herbicidal composition comprising asan essential active ingredient homogeneously dis- 9 persed in a non-solvent fluent carrier with a surface active agent, 1-cyc1ohexy1-3,3-dimethylurea. 7. A 1-cyc1ohexy1-3,3-dia1ky1urea having the formula CH2 CHN("JNR' \CH2C2 15 Ill wherein R and R are alkyl radicals.

8. The chemical compound, 1-cyc1ohexyl-3,3- dimethylurea.

9. A herbicidal method which comprises applying to a locus to be protected from weeds a composition containing a 1-cyc1ohexyl-3,3-dialkylurea as an essential herbicidal agent in effective amount.

10 10. A herbicidal method which comprises applying to a locus to be protected from weeds a composition containing 1-cyc1ohexy1-3,3-dimethylurea as an essential herbicidal agent in effective amount.

NORMAN E. SEARLE.

' References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,374,485 Haury Apr. 24, 1945 2,477,872 Haury Aug. 2, 1949 OTHER REFERENCES Dieke et al., J. Pharmacol," v01. (1947), pages 260, 264. 

7. A 1-CYCLOHEXY-3,3-DIALKYLURA HAVING THE FORMULA
 9. A HERBICIDAL METHOD WHICH COMPRISES APPLY ING TO LOCUS TO BE PROTECTED FROM WEEDS A COMPOSITION CONTAINING A 1-CYCLOHEXY-3,3-DIALKYLUREA AS AN ESSENTIAL HERBICIDAL AGENT IN EFFECTIVE AMOUNT. 